Nice one Mick! Much better than my first go at this object and better than my last go at it. I posted my last effort in the Deep Space section a few weeks ago and yours definitely deserves to be there as well. I know how tough this target is to capture so can appreciate the result you've achieved. Clever processing too, separating the nebula from the stars to do more work on the nebula and recombine the stars in later. Great job.
PS. I had a go at making a mask in PS to remove the stars and work on enhancing the nebula. I then introduced the worked nebula back into the original picture as a "Lighten" layer and this helped the contrast in my shot. Great idea inspired by what you had done. Another processing trick up the sleeve!